Gas operated bolt mechanism

ABSTRACT

A gas operated bolt carrier imparts reciprocating movement to a bolt body through a locking sleeve angularly displaceable on the bolt to a striker blocking position thereby preventing firing when the bolt is displaced from its battery position. A locking slot formed in the receiver prevents angular movement of the locking sleeve following initial retraction of the bolt from the battery position by the bolt carrier.

limited States Patent 1191 Segre st July 16, 1974 GAS OPERATED BOLT MECHANISM Primary Examiner-Stephen C. Bentley [.75] lnventor' Doyle E. Segrest woodvme Tax Attorney, Agent, or Firm-Clarence O. OBrien; Har- 73] Assignee: Texas Automatics, Inc., Woodville, vey. B, Jacobson Tex.

[22] Filed: Oct. 3, 1973 [57] ABSTRACT [21] Appl. No.: 402,985 A gas operated bolt carrier imparts reciprocating movement to a bolt body through a locking sleeve angularly displaceable on the bolt to a striker blocking gz f position thereby preventing firing when the bolt is dis- 58] Fieid 89/13 4 174 placed from its battery position. A locking slot formed in the receiver prevents angular movement of the locking sleeve following initial retraction of the bolt [56] g gi'f gzf from the battery position by the bolt carrier. 1,159,004 11/1915 Frommer 89/154 7 Claims 9 Drawing Figures GAS OPERATED BOLT MECHANISM The present invention relates to firearms of the boltaction type and more particularly to gas operated boltaction firearms such as disclosed in my prior US. Pat. No. 3,329,064.

Gas operated, bolt-action firearms are generally well known and embody an integral bolt body that is slidably mounted with the ordnance receiver of the firearm for slidable displacement by a bolt carrier from a firing or battery position into the breech end of the receiver. Displacement of the bolt body is effected through a bolt carrier as disclosed in my prior U.S. patent aforementioned initially effecting angular movement of the bolt body during its slidable retraction into the breech end of the receiver in order to preclude untimely impact of the firing pin by the striker element of the trigger mechanism. The combined axial and angular movement of the bolt body accounts for a considerable amount of frictional wear and misfiring. It is therefore an important object of the present invention to provide a bolt-action firearm of the above mentioned type wherein the bolt bodyis non-rotatable and wherein untimely engagement of the firing pin by the striker is prevented in a more reliable fashion so as to avoid damage to the firearm from any misfiring.

In accordance with the present invention, a tailpiece locking sleeve is mounted on the bolt body of a boltaction firearm for limited angular displacement relative to the bolt body. During initial slidable displacement of the bolt from its battery or firing position by the bolt carrier, a limited amount of angular movement is imparted to the locking sleeve in order to bring it to a blocking position preventing engagement of the striker with the firing pin. The locking sleeve is locked in this blocking position on the bolt during the remainder of its rearward travel into the breech end of the receiver. A locking slot is formed in the receiver for this purpose receiving the camming lug which projects from the locking sleeve into a spiral groove formed inthe bolt carrier. The locking slot is encircled within a sleeve fitted onto a reduced diameter breech end portion of the receiver closed by a breech plug. Angular movement of the locking ring is limited by a lateral recess formed therein slidably receiving a guide rail formation on the tubular receiver of the firearm into which shotgun shells for example, are displaced from a magazine associated with the firearm.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

FIG. 1 is a partial side elevational view of a rear end portion of a firearm constructed in accordance with the present invention.

FIG. 2 is a top plan view of the rearend portion of the firearm shown in FIG. 1.

FIG. 3 is an enlarged transverse sectional view taken substantially through a plane indicated by section line 3-3 of FIG. 1.

FIG. 4 is a partial side sectional view taken substantially through a plane indicated by section-line 44 in v FIG. 3.

FIGS. 5 and 6 are transverse sectional views taken substantially through a plane indicated by section lines 55 and 6-6 in FIG. 4.

FIG. 7 is a partial side sectional view similar to that of FIG. 4 showing the bolt assembly in a partially retracted position.

FIG. 8 is a partial side sectional view taken substantially through a plane indicated by section line 8-8 in FIG. 7.

FIG. 9 is a partial transverse sectional view taken substantially through a plane indicated by section line 9-9 in FIG. 7.

Referring now to the drawings in detail, FIGS. 1 and 2 illustrate a rear end portion of a typical firearm generally referred to by reference numeral 10 which includes a barrel 12 extending forwardly from a tubular receiver 14 closed at the breech end by a plug 16. Ordnance rounds such as shotgun shells are fed to the receiver 14 from a magazine 18. Operation of the firearm is effected in a conventional manner by a bolt action as disclosed in my prior US. patent aforementioned wherein the bolt is retracted by means of a gas operated rod through a bolt carrier 22. The bolt carrier is manually-retracted by means of a laterally extending finger knob 24 in order to load the first shell into the receiver from the magazine. Loading of shells is effected thereafter automatically by gas pressure generated in response to firing of a preceding shell. As the bolt carrier is retracted toward the recoil position at the breech end of the receiver, the ejection port 26 in the receiver is completely uncovered to permit ejection of the shell casing that is retracted by the bolt in a conventional manner. The receiver 14 is furthermore provided with a locking slot 28 that extends rearwardly from the ejection port toward the breech end of the receiver and is operative to positively prevent any unintentional and untimely actuation of the firing pin associated with the bolt as will be explained in detail hereafter.

As more clearly seen in FIG. 4, the receiver 14 is attached to the barrel 12 by means of a flange 28, the receiver being of somewhat larger diameter than the barrel and slidably mounting a bolt body generally referred to by-reference numeral 30 adapted to be axially displaced between the battery or firing position shown in FIG. 4 and a fully retracted position adjacent the breech end of the receiver through which the locking slot 28 extends. The breech end portion 32 of the re ceiver is of reduced diameter so as to form a shoulder 34 and is internally threaded so as to receive the externally threaded portion 36 of the plug 16. A sleeve 38 is mounted on the breech end ,portion 32 of the receiver in encircling relation to the slot 28 and is held assembled between, the shoulder 34 and the knurled portion of the plug' 16. The bolt carrier 22 is slidably mounted externally on the receiver 14 and as shown in FIGS. 1 and 2, is provided with a spiral camming groove 40 adapted to receive a lug 42 that projects radially form a locking sleeve 44 associated with the bolt 30.

Referring now to FIGS. 3'and 4, the bolt 30 includes a forward end portion 46 of larger diameter and a rear end portion 48 of smaller diameter on which the locking sleeve 44 is mounted for limited angular displacement relative to the longitudinal axis of the bolt. An angular groove 50 is formed within the tail end portion 48 of the bolt adjacent its rear end 52 for receiving a retainer screw 54 secured to the locking sleeve 44 in order to prevent relative axial movement between the locking sleeve 44 and the bolt. The locking sleeve includes a reduced diameter extension 56 that projects rearwardly beyond the bolt and is provided with a support wall 58 adjacent its rear end having an opening for slidably supporting the hammer end portion 60 of a firing pin generally referred to by reference numeral 62. The firing pin is slidably carried within a central bore 64 of the bolt and is rearwardly biased to the position shown in FIG. 4 by a spring 66. The firing pin is retained in the position shown by means of a retaining pin 68 extending radially inwardly from the bolt body into the bore 64. The hammer end portion 60 of the firing pin projects a slight distance-rearwardly beyond the support wall 58 within an annular end abutment rim 70 formed with a notch 72 as more clearly seen in FIGS. 4 and adapted to be aligned with a striker element 74 associated with the trigger mechanism. In the position shown in FIGS. 4 and 5, the locking sleeve 44 is in an angular limit position wherein the slot 72 is aligned with the striker element 74 so that it may engage the hammer end portion 60 of the firing pin. This is the operative firing position for the locking sleeve 44 and associated bolt 30 which abuts the flange end portion 76 of a shotgun shell 78 loaded into the barrel 12 of the firearm as shown in FIG. 4. The shell is fired as is well known by those skilled in the art by an impact applied to the firing pin 62 through the striker resulting in the generation of gas which is operative through the gas actuated rod and bolt carrier 22 to rearwardly retract the bolt 30 toward a fully retracted position withdrawing the shell casing 80 therewith from the barrel by means of pivoted extractor elements 82 as more clearly seen in FIGS. 7, 8 and 9. The empty shell casing 80 is accordingly ejected from the firearm through the ejection port 26 in a manner well known to those skilled in the art. When the bolt 30 is fully retracted, a new shell 78 is displaced from the magazine 18 into the receiver so that it may be forwardly moved to the firing position by return movement of the bolt from the fully retracted position to the battery position.

The bolt carrier 22 is mounted externally on the tubular receiver 14 for non-rotatable, sliding movement relative thereto. It is operatively connected to the bolt 30 through the locking sleeve 44 in order to transmit axial movement to the bolt. This operative connection includes the spiralgroove 40 in the bolt carrier aforementioned and the lug 42 by means of which initial rearward displacement of the bolt carrier imparts angular movement to the locking sleeve 44 so as to displace it from the angular limit position in which the hammer end 60 of the firing pin is engageable by the striker element 74. The cam lug 42 therefore extends radially from the locking sleeve 44 which is also provided with on one side with an arcuate recess 84 as more clearly seen in FIGS. 3 and 6 slidably receiving a guide rail formation 86 projecting radially inwardly from the tubular receiver 14. Accordingly, the locking sleeve 44 may undergo limited angular displacement relative to the receiver and the bolt body 30, such angular displacement being imparted thereto in response to rearward slidable displacement of the bolt carrier 22 through the camming groove 40 and the lug 42. When the locking sleeve 44 is angularly displaced from the position shown in FIGS. 3 and 6, to its other limit position, the locking lug will be aligned with the locking slot 28 in the receiver. Accordingly, during continued rearward displacement of the bolt carrier 22, the locking slot 28 will guide rearward displacement of the locking sleeve 44 with the bolt and the bolt carrier 22 and at the same time positively prevent any angular displacement of the locking sleeve from its blocking position. In the blocking position, the slot or notch 72 in the abutment rim 70 will be angularly displaced out of alignment with the striker element 74 so as to prevent the striker element from engaging the firing pin as a result of untimely actuation of the trigger mechanism. The slot 72 will only be operatively aligned with the striker element when the locking sleeve 44 is returned to its angular limit position on the bolt body corresponding to the position of the bolt in the battery position shown in FIG. 4.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact constructon and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. construction What is claimed as new is as follows:

1. In a firearm having a tubular receiver, a bolt mounted for non-rotatable, reciprocating movement between a battery position and a retracted position within the receiver, a firing pin slidably carried in the bolt, a bolt carrier slidably mounted externally on the receiver and a striker engageable with the firing pin rearwardly of the bolt in the battery position; means operatively connecting the bolt carrier to the bolt comprising a locking sleeve rotatably mounted on the bolt, retainer means preventing relative axial movement between the locking sleeve and the bolt, camming means for imparting angular movement to the locking sleeve toward a lock position in response to slidable movement of the bolt carrier on the receiver, and blocking means mounted on the locking sleeve for preventing engagement of the firing pin by the striker in response to said angular movement toward the lock position upon displacement of the bolt from the battery position by the bolt carrier.

2. The combination of claim 1 wherein said blocking means includes a rearward extension of the locking sleeve, an abutment connected to the extension through which the firing pin is exposed to the striker, said abutment having an opening aligned with the striker only in the battery position of the bolt to permit engagement of the firing pin by the striker.

3. The combination of claim 2 wherein said camming means includes a spiral groove in the bolt carrier and a lug projecting from the locking sleeve into the spiral groove, said receiver being provided with an ejection port and a locking slot extending rearwardly therefrom through which the lug extends into the spiral groove, said locking slot preventing angular displacement of the locking sleeve from said lock position.

4. The combination of claim 3 wherein said receiver includes a breech end portion of reduced diameter through which the locking slot extends, a breech plug received in said end portion, and a sleeve mounted on the end portion in abutment with the plug. v

5. The combination of claim 1 wherein said camming means includes a spiral groove in the bolt carrier and a lug projecting from the locking sleeve into the spiral groove, said receiver being provided with an ejection port and a locking slot extending rearwardly therefrom bolt, a bolt carrier slidably mounted externally on the receiver and a striker engageable with the firing pin rearwardly of the bolt in the battery position, a locking device rotatably mounted on the bolt for angular movement in response to rearward displacement of the bolt carrier, camming means for imparting said angular movement to the locking device while transmitting axial movement to the bolt from the battery position, and means mounted on the receiver for holding the locking device in an angular blocking position preventing the striker from engaging the firing pin. 

1. In a firearm having a tubular receiver, a bolt mounted for non-rotatable, reciprocating movement between a battery position and a retracted position within the receiver, a firing pin slidably carried in the bolt, a bolt carrier slidably mounted externally on the receiver and a striker engageable with the firing pin rearwardly of the bolt in the battery position; means operatively connecting the bolt carrier to the bolt comprising a locking sleeve rotatably mounted on the bolt, retainer means preventing relative axial movement between the locking sleeve and the bolt, camming means for imparting angular movement to the locking sleeve toward a lock position in response to slidable movement of the bolt carrier on the receiver, and blocking means mounted on the locking sleeve for preventing engagement of the firing pin by the striker in response to said angular movement toward the lock position upon displacement of the bolt from the battery position by the bolt carrier.
 2. The combination of claim 1 wherein said blocking means includes a rearward extension of the locking sleeve, an abutment connected to the extension through which the firing pin is exposed to the striker, said abutment having an opening aligned with the striker only in the battery position of the bolt to permit engagement of the firing pin by the striker.
 3. The combination of claim 2 wherein said camming means includes a spiral groove in the bolt carrier and a lug projecting from the locking sleeve into the spiral groove, said receiver being provided with an ejection port and a locking slot extending rearwardly therefrom through which the lug extends into the spiral groove, said locking slot preventing angular displacement of the locking sleeve from said lock position.
 4. The combination of claim 3 wherein said receiver includes a breech end portion of reduced diameter through which the locking slot extends, a breech plug received in said end portion, and a sleeve mounted on the end portion in abutment with the plug.
 5. The combination of claim 1 wherein said camming means includes a spiral groove in the bolt carrier and a lug projecting from the locking sleeve into the spiral groove, said receiver being provided with an ejection port and a locking slot extending rearwardly therefrom through which the lug extends into the spiral groove, said locking slot preventing angular displacement of the locking sleeve from said lock position.
 6. The combination of claim 5 wherein said receiver includes a breech end portion of reduced diameter through which the locking slot extends, a breech plug received in said end portion and a sleeve mounted on the end portion in abutment with the plug.
 7. A firearm including a tubular receiver, a bolt mounted for non-rotatable, reciprocating movement between a battery position and a retracted position within the receiver, a firing pin slidably carried in the bolt, a bolt carrier slidably mounted externally on the receiver and a striker engageable with the firing pin rearwardly of the bolt in the battery position, a locking device rotatably mounted on the bolt for angular movement in response to rearward displacement of the bolt carrier, camming means for imparting said angular movement to the locking device while transmitting axial movement to the bolt from the battery position, and means mounted on the receiver for holding the locking device in an angular blocking position preventing the striker from engaging the firing pin. 